This invention relates to a fastening member of the type which is molded into molded foam cushions, such as seat cushions used in automobiles and other vehicles. The fastening members have hooks which mate with complementary fastening members which are attached to the inside of seat upholstery. When mated the fastening members position and secure the upholstery to the seat cushion. Prior art devices, including prior patents to the present assignee, include a covering film which encloses and protects the hooks of the fastening member from molding liquid until the liquid has cured and turned into a solid foam material. Then, the covering film is removed to expose the hooks and permit the fastening member to be used for its intended purpose.
The fastening members are generally held in mold pockets in the mold by magnetic attraction. The mold pockets contain powerful magnets. Most commonly, the covering film of the fastening member is bonded to intermittent strips of steel shim stock, which are attracted to the magnets in the mold pocket and hold the fastening member in the mold pocket. See, e.g., applicant's U.S. Pat. Nos. 4,933,035 and 4,693,921.
An alternative arrangement is shown in U.S. Pat. No. 4,784,890. In '890, a ferromagnetic coating is applied to the marginal areas of the fastening member along either side of the upstanding hooks. The ferromagnetic coating is intended to create a sufficiently good seal between the mold pocket and the fastening member that the protective film covering such as shown in the '035 and '921 Patents is unnecessary. Thus, the film removal step after molding is complete is eliminated in the '890 Patent.
However, the fastening member using the protective film covering has become the predominant method of using this form of seat upholstery attachment, since it is easier to position in the mold pocket and a more secure seal against molding liquid contamination of the hooks is provided. As noted above, this film must be removed before the fastening member can be used. It has been found that occasionally the removed protective film with the attached steel shim stock is inadvertently swept up with foam scraps for recycling. Scrap foam contaminated with this steel material is unusable. The protective film with the attached steel shim stock is also difficult to dispose of, since it is not recyclable either as a metal or plastic.
It has also been observed that if the steel shim stock becomes bent, it may cause the fastening member to bend as well, thus causing the fastening member not to lie flat in the mold pocket. In other words, the steel shim stock reduces the flexibility of the fastening member to a considerable extent.
The present invention solves these problems by utilizing a ferromagnetic coating in combination with the protective film covering the hooks of the fastening member, as described and claimed below.